R help - Nov 2011 - rbind.data.frame drops attributes for factor variables

Hi all,

When I use rbind() or rbind.data.frame() to add a row to an existing
dataframe, it appears that attributes for the column of type "factor"
are
dropped. I see the following post with same problem. However i did not see
any reply to the following posting offering a solution. Could someone
please help.

http://r.789695.n4.nabble.com/rbind-data-frame-drops-attributes-for-factor-variables-td919575.html

Thanks,
Sanjay

	[[alternative HTML version deleted]]

As the doctor says, if it hurts "don't do that".

A factor is a sequence of integers with a corresponding list of character
strings. Factors in two separate vectors can and usually do map the same integer
to different strings, and R cannot tell how you want that resolved.

Convert these columns to character before combining them, and only convert to
factor when you have all of your possibilities present (or you specify them in
the creation of the factor vector).
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Sammy Zee <szee2007 at gmail.com> wrote:
>Hi all,
>
>When I use rbind() or rbind.data.frame() to add a row to an existing
>dataframe, it appears that attributes for the column of type
"factor"
>are
>dropped. I see the following post with same problem. However i did not
>see
>any reply to the following posting offering a solution. Could someone
>please help.
>
>http://r.789695.n4.nabble.com/rbind-data-frame-drops-attributes-for-factor-variables-td919575.html
>
>Thanks,
>Sanjay
>
>	[[alternative HTML version deleted]]
>
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